I had this game pretty early on in early access, and I have enjoyed it very much. I play single player mostly, as I generally do not like MP games, because of the hackers, and lag, and D bags. Especially for this type of game, MP can be a nightmare. This game has a slow progression, so if you are new on a server with an Alpha tribe, don't be surprised if an armored player shoots you with high powered weaponery, when you are running around naked with sticks trying to start out, and then he says "it's PVP". People can be terrible to play with. Not all of them. Some are really cool. But the bad ones ruin it for all. I think this is the reason for all the bad reviews.
It is a survival game with dinosaurs. The animals are well modeled, and have different abilities when you tame them. When you start you are in danger almost constantly, and as you progress, you learn what to do, what's where, you increase your characters abilities, like melee strength, health, stamina, speed, and other things. You learn how to build different things to help you out, and as you advance life get a little easier. But you can always find a challenge. Sometimes, I like riding around and watching the different animals interacting. It is extremely beautiful at times.
The amount and variety of animals is staggering.
The crafting tree (engrams) is huge.
What you can build is impressive.
What you can do is impressive. Plant crops, hunt, tame, build, craft, boat, swim, mine, collect, fight bosses, paint or dye things, ect...
There are workshop mods, if you are into that.
If you play single player, there are sliders to change many different things, including taming speed, night day cycle times pretty much everything to make it to your liking. To make it as grindy, more or less, as you like.
The Devs did a great job on this game.
Single player is how I like it.
Private server with friends would be great fun, but persistent public servers with randoms... expect it to be terrible.